Not sure where you are getting your info, but Fj and all the older toyota Pu 4x4 all use the same steering knuckle which is a relativly small dia meter, refer to the added picture, and reference the size of the disc about 12" to the size of the knuckle (half the size) FJ knuckles and all toyota closed knuckle axles are tiny at 6" plus or minus.

Steering Knuckle, FJ, BJ, HJ, FZJ, HDJ, HZJ, 40, 45, 55, 60 And 80 Series Toyota Land Cruiser.

References:

https://www.fjparts.com/knuckle-c-21_189.html

Reason:
Hey, I think you are correct that it is a Knuckle housing, but the FJs are MUCH larger than this one. Would different pictures or measurements help you?

Not sure where you are getting your info, but Fj and all the older toyota Pu 4x4 all use the same steering knuckle which is a relativly small dia meter, refer to the added picture, and reference the size of the disc about 12" to the size of the knuckle (half the size) FJ knuckles and all toyota closed knuckle axles are tiny at 6" plus or minus.

References:

http://image.fourwheeler.com/f/42769872+w660+h440+q80+re0+cr1+ar0/1210-4wd-07...